Motion e.m.f. generating transducer



May 5, 1954 M. l.. ABEL ETAL 3,132,263

MOTION E.M.F. GENERATING TRANSDUCER Filed March 5, 1962 2 Sheets-Sheet 1i 0 5 H (3542 52 mm. 24M j.;

:ll.l I iw "uw f .50 4 sa/@awww 4 '5 45@ E' 96. f/// 24- m d 7 f minimunK25 wif #1:, ulm!! May 5, 1964 M. l.. ABEL ETAL 3,132,268

MOTION E.M.F. GENERATING TRANSDUCER Filed March 5, 1962 2 Sheets-Sheet 2JZ f2 BY f7 W35@ United States Patent Oiiic/e Mich., assignors to ForceControls Company, Ferndale,

`Mich., a corporation of Michigan Filed Mar. 5, 1962, Ser. No. 177,59710 Claims. (Cl. S10-15) This invention relates to a generator of thetype adapted to sense a condition and to operate an electrical circuitin response thereto. More particularly, the invention Consists in theprovision of a transducer and a triggering device associated therewithfor energizing the transducer to operate an electrical control circuitin response to movement of the triggering device. The invention ischaracterized by the fact that the triggering device includes a movablecontact button which will energize the transducer to generate a controlsignal of constant strength independent of the rate fat which thecontact kbutton is moved. The point at which the triggering deviceenergizes the transducer is also very accurately controlled so that thecontrol signal is generated at a precise point within extremely smalltolerances during each cycle of operation.

A principal object of the invention is to provide a new and improvedgenerator for operating an electrical circuit.

Another object of the invention is to provide a generator comprising atransducer and a triggering device therefor which will energize thetransducer to operate a solid state electrical circuit which performs aswitching function with extreme accuracy.

Another object of the invention is to provide a triggering device for atransducer ywhich will energize the transducer to cause the latter toemita control signal of constant strength regardless of the rate ofmovement of the triggering device.'

y #Other and further objects of the invention will be apparent lfrom thefollowing description and claims and may be understood byy reference tothe accompanying drawings,

of which there are two sheets, whichby way'of illustration showpreferred embodiments of the invention and what we now considerto be thebest mode of applying the principles thereof. Other embodiments of theinvention may ybe used without departing from the scopey of thepresentinf vention as set forth inthe appended claims.

In the drawings: t n

FIG. l is an elevational Iview of a generator according to the presentinvention; v FIG. 2 is an enlarged sectional view taken on line 2 2 ofFiG. l;

FIG. 3 is a view similar to FIG. 2 but showing the parts in a differentoperative position thereof;-y r

FIG. 4 is a sectional view taken on line 4 4 of FIG. 2;

TIG. 5 is a sectional view taken on line 5--5 of FIG. 2;

FIG. 6 is a sectional View illustrating a modified form of theinvention;and y p FlG. 7 is a circuit diagram illustrating one type of electricalcircuit that may be used in conjunction with the transducer.

yThe presentinvention comprises a transducer 10 to-k gether with atriggering device 12, bothk contained Within a tubular housing 14.yReferring to FIG. 5, the transducer 10 comprises a pair offiron'coresor pole pieces 16 each having a coil ftd of `fine wire wrapped aroundone end thereof anda permanent magnet Ztifdisposed between the otherends of the cores 16. The coils 18 are wound onto insulating spools 22which are fitted over the ends v a force transmitting member which willimpart movement n Patented May 5, 1964 end thereof, with the lead wires28 extending outwardly through a threaded opening 39 inthe housing 14.

iT he triggering device 12 comprises a contact button 32 which isexteriorly threaded to receive a lock nut 34 which engages a collar 36which is also threaded onto the contact button l32 and is provided witha radial shoulder v38 engaging within a counterbore 40 in a sleeve 442which is slidable within they bore 44 defining the inner wall of thehousing 14; An exteriorly threaded washer 46 is threaded into the outerend of the bore 44 and is engaged by the sleeve 42 and the collar 36 toprovide a stop limiting outward movement of such parts.`

An armature consisting of a soft iron disc y48 secured to a member 5@ isslidable within the central bore 52 of the sleeve 42. A shoulder 54 onthe member'SO engages the inner end of the sleeve 42 and is heldthereagainst by a spring 56 which is secured at one end to a pin 58extending across a recess 6i) in the contact button 32 and `secured atits other end to a pin 62 disposed within a recess 64 in the member Sti.Obviously the disc 48 and the member 5@ may be made integral is desired.A spring do is confined ybetween one end of the sleeve 24 and a radialshoulder 68 on the sleeve 42 and urges the latter against the stop 46. yf y. y

'llhe contact button 32 is adapted to be yengaged by tothe Contactbutton in response to a change inthe condition being sensed. The partsare shown in FlG. 2 in the position they occupy when the force appliedto the contact button 4has not ye'treached a value suiicient to depressn Athe contact button out of engagement with the stop 46.

y As the contact button 32 is depressed, the collar 38, sleeve of thecores 16. yThe permanent magnet 2t) is arranged n so that one of itspoles faces one of the cores 16 while its opposite pole faces the othercore 16. The transducer is encased within an insulating sleeve 24 whichis inserted into the housing 14 to abut a shoulder `26 at thek inner 42and armature 48 will be depressed as a unit against the force of thespring 66 to move ythe armature toward the exposed ends 70 of the cores16 which extend a slight distance beyond the outer end '72 of thepermanent magnet 20. When the armature 48 is spaced a certainpredetermined distance rom the ends 7d of the cores 16, the magnetic`force will snap the armature 48 into engagement with thecores 16against the force of spring 56, thereby moving thelines of flux over thecoils 18 to induce an eleetromotive force which is supplied to a solidstate electrical circuit indicated generally at 72 in FIG. 7, which isdesigned to perform a switching function to control any suitableelectrical component such as a solenoid valve.

It will be seen that the strength of the control signal thatis generatedin the transducery 1G is independent of the rate at which the contactbutton 32 is depressed because the armature 4S is free to move away fromthe sleeve 42 into engagement with the cores 16 when themagv45approaches the cores-16, so that the rapid movement ofthe armature intoengagement with the cores will occur at aprecisely controlled point orat a precise spacing of the armature from the cores. The parts are shownin FIG. 3 in the position they occupy after the armature has been pulledinto engagement with the pole `pieces to generate a control vsignal. Therate at which 'the armature is snapped into yengagement with the poleswill always be the same so that the strengthof the signal emittedwilljbe constant `and independent of the rate at which the contactbutton is depressed. y n L v As the contact button is released, anothercontrol signal is generated which will also beof constant strength andindependent of the rate of movement of the contact button.

the magnetic attraction thereof. The spring 56 is thereby stretched toexert an increasingly greater pull on the armature and, when the forceexerted by the spring 56 exceeds the magnetic force, the. armature .willbe pulled rapidly away from the cores 16 into engagement with the sleeve42, thereby inducing another control signal in the coils 18.

The device may be made to accurately detect the position of an objectwhichengages the contact button by means of a micrometer adjustmentwhich comprises an exteriorly threaded sleeve 80'which is axiallyslidably but nonrotatably mounted on the exterior of the housing 14 bymeans of a key 82. A collar 84 is xedly secured on theI housing 14 andis exteriorly threaded to mesh with a Calibrating sleeve 86 providedwith an inwardly turned shoulder 88 engaging an outwardly extendingshoulder 90 ,on the sleeve 80. The sleeve 80 is threaded into a threadedopening in a wall indicated at 92 to engage the contact button 32 withthe load or a force transmitting member. The inwardly turned shoulder 88on the calibrating sleeve 86 abuts against the wall 92 and also isengaged by the shoulder 90 on the sleeve 80. The sleeve 86 is providedwith micrometer markings 94, and a Stationary part such as the wall 92may be provided with a hairline so that the proper micrometer marking onthe sleeve r86 which may be in pounds of torce can be aligned therewith.As the micrometer sleeve 86 is rotated, the housing 14 and the threadedcollar 84 carried thereby and meshed with the micrometer sleeve willslide axially inwardly or outwardly through the sleeve 80 until thedesiredreading is obtained. This adjustment of course varies theposition of the contact button relative to the force transmitting memberso that the device may be made to generate the control signal at anyselected value. The micrometer sleeve may be locked by a lock nut 96.

The transducer may be used in conjunction with any suitable circuitsuch` as the circuit 72 shown in FIG. 7, which is illustrative only. Thecircuit shown in FIG. 7 may comprise the coils 18 which are wound sothat the voltage developed in the coils as the armature is moved towardor away from the ends of the cores 16 will be of opposite polarity. Thecircuit further includes transistors 100 and 102, resistances 104, 106,108 and 110, and an output terminal 112. The output terminals of thetransistors 100 and 102 are indicated at To and To' respectively. Whenpower is supplied to the circuit, one of the transistors will shortly beconducting the current while the other is cut off, which constitutes oneof the two stable states of the circuit. If, for example, the transistor100 is conducting and the armature 48 is moved into engagement with theends of the cores 16 in the manner described so as to produce a negativevoltage exceeding the voltage developed across resistor 104 to beapplied tothe base of transistor 102 and a positive voltage to beapplied to the base of transistor 100, transistor 102 will then startconducting and reducing the amount that transistor 100 is conducting,which action once begun will continue rapidly until transistor 102 isconducting heavily while transistor 100 is cut oi. The output may thenby taken from the collector of transistor 102. This repre- Vsents theother stable state of the circuit. When armature 48 is moved away fromthe cores 16,A another voltage is generated which will be negative onthe base of transistor 100 and positive on the base of transistor 102,thereby to return the circuit to its other stable condition. The circuitis therefore a switching circuit and may be used to control any suitableelectrically operated device such as a solenoid operated valve, anignition circuit, or any other electrically actuated device. It will beapparent that other types of switching circuits may be employed and thatthe circuit illustrated forms no part of Ythe present invention. v

In the form of the invention illustrated in FIG. 6, the transducer maybe of the same construction previously described and in this case it iscontained within a threaded ,Y 4 insulating casing 120 which is threadedinto an internal shoulder 122 formed in thewhousing 124. At its otherend the housing 124 is threaded to receive a stop collar 126 having arecess 128 and a coaxial bore 130 within which the contact button 132reciprocates. A spring 134 is conined between the contact button 132 andan annular disc 136 which engages an internal shoulder on the sleeve138. A spring 140 conned between the internal shoulder 122 on thehousing and the sleeve 138 urges the sleeve 138 and the disc 136 intothe engagement with the collar 126.

. The armature 142 is secured to a rod 144 which extends slidablythrough the bottom wall 146 of the housing 138. Arspring 148 is confinedbetween the wall 146 of the sleeve and a washer 150 on the rod 144 whichengages a nut 152. threaded onto the outer end of the rod 144. When thecontact button 132 is depressed by a force applied thereto, the spring134 will be compressed and eventually will force the disc 136 and sleeve138 `in Wardly against the spring 140 carrying the armature 142 towardthe cores of the transducer. At a predetermined point, the magneticforce will rapidly move the armature 142 into engagement withthe cores,thereby compressing spring 148. When the force applied to the contactbutton is reduced, the spring 140 will move the sleeve 138 outwardly,further compressing spring 148 until the force of the latter springexceeds the magnetic force holding the armature in position and at apredetermined point the armature will move rapidly out of engagementwith the cores, thereby generating a second control signal. The deviceshown in FIG. 6 may also be provided with a micrometer adjustment ifdesired. The spring 134 allows some overtravel of the contact button 132beyond that necessary to energize the transducer.

Since the rate at which the armature in either form of the inventionmoves toward the cores of the transducer is independent of the rate ofmovement of the Contact K button, the transducer will always generate asufficiently strong signal of constant value to operate the controlcircuit. Thus with the present construction it is not possible-for thecontact button to be moved so slowly as to fail to induce suicientcurrent in the coils to energize the control circuit as is possible withprior art devices.

While we have illustrated and described preferred embodiments of ourinvention, it is understood that these are capable of modification, andwe therefore do not wish to be limited to the precise details set forthbut desire to avail ourselves of such changes and alterations as fallwithin the purview of the following claims.

We claim:

l. Ina device for sensing a condition and operating an electricalcircuit in response thereto including a core having a coil wound thereonand a permanent magnet associated therewith, an armature movable intoand out of engagement with said core, an actuating member adapted formovement in response to change in the condition being sensed, a motiontransmitting connection between said armature and said actuating memberso that said armature is movable with said actuating member toward saidcore until said armature is spaced a predetermined distance from saidcore whereupon the magnetic attraction causes said armature to snap intoengagement with said'core therebyto induce a current in said coilindependent of the rate of movement of said actuating member, and aspring connecting said actuating member and said armature for urgingsaid armature into engagement with said actuating member but permittingmovement of the latter away from said core while said armature remainsin engagement therewith until said spring overcomes said magneticattraction and pulls said armature away from said core and intoengagement with said actuating member thereby to induce a second currentin said coil independent of the rate of movement of said actuatingmember.

2. In combination with a transducer device including a core having acoil wound thereon and a permanent aisance magnet associated therewith,a triggering device for energizing said coil in response to a change ina condition being sensed, comprising an armature movable into and out ofengagement with said core, an actuating member adapted for movement inresponse to change in the condition being sensed, a motion transmittingconnection between said armature and said actuating member so that saidarmature is movable with said actuating member toward said core untilsaid armature is spaced a predetermined distance irom said corewhereupon the magnetic attraction causes said armature to snap intoengagement with said core thereby to induce a current in said coilindependent of the rate of movement of said actuating member, and aspring connecting said actuating member and said armature for urgingsaid armature into engagement with said actuating member but permittingmovement of the latter away from said core while said armature remainsin engagement therewith until said spring pulls said armature away fromSaid core and into engagement with said actuating member thereby toinduce a second current in said coil independent of the rate of movementof said actuating member.

3. ln a transducer for sensing a condition and operating an electricalcircuit in response thereto including a core having a coil wound thereonand a permanent magnet associated therewith, an armature movable intoand out of engagement with said core, an actuating member adapted formovement in response to change in the condition being sensed, a motiontransmitting connection between said armature and said actuating memberso that said armature is movable with said actuating member toward saidcore until said armature is spaced a predetermined distance from saidcore whereupon the magnetic attraction causes said armature to snap intoengagement with said core thereby to induce a current in said coilindependent of the rate of movement of said actuating member.

4. A transducer according to claim 3 including spring means urging saidarmature into engagement with said actuating member.

5. A transducer according to claim 4 including a spring urging saidacuating member away from said core.

6. in a transducer for sensing a condition and operating an electricalcircuit in response thereto, a pair of iron cores each having a coilwound thereon at one end thereof and a permanent ceramic magnet betweenthe opposite ends of said cores, a housing, said transducer beingmounted in one end of said housing, a triggering device mounted withinthe other end of said housing comprising an actuating member slidablymounted in said housing for movement toward and away from saidtransducer, a stop limiting movement of said actuating member away fromsaid transducer, a spring urging said actuating member into engagementwith said stop, an armature slidably mounted on said actuating memberand opposed to the ends of said cores, said actuating member engagingsaid armature so that said armature is movable therewith toward saidcores as a load is applied to said actuating member until said armatureis spaced a predetermined distance from said cores whereupon themagnetic attraction causes said armature to snap into engagement withsaid cores thereby to induce a current in said coils the value of whichis independent of the rate of movement of said actuating member', and aspring connecting said actuating member and said armature permittingmovement of said actuating member away from said cores while saidarmature remains in engagement therewith as the load on said actuatingmember is decreased ti until said spring pulls said armature away fromsaid cores and into engagement with said actuating member thereby toagain induce a current in said coils the value of which is independentet the rate of movement of said actuating member.

7. lin an actuating device for a transducer including a core having acoil wound thereon and a permanent magnet associated therewith, anarmature movable into and out of engagement with said core, an actuatingmember, a motion transmitting connection between said armature saidactuating member so that said armature is movable with said actuatingmember toward said core until said armature is spaced a predetermineddistance from said core whereupon the magnetic attraction causes saidarmature to snap into engagement with said core thereby to induce acurrent in said coil independent of the rate of movement of saidactuating member.

8. ln an actuating device for a transducer including a core having acoil wound thereon and a permanent magnet associated therewith, anarmature movable into and out of engagement with said core, an actuatingmember, a motion transmitting connection between said armature and saidactuating member so that said armature is movable with said actuatingmember toward said core until said armature is spaced a predetermineddistance from said core whereupon the magnetic attraction causes saidarmature to snap into engagement with said core thereby to induce acurrent in said coil independent of the rate or" movement of saidactuating member, and a spring ,rging said armature into engagement withsaid actuating member but permitting movement of the latter away fromsaid core while said armature remains in engagement therewith until saidspring overcomes said magnetic attraction and pulls said armature awayfrom said core and into engagement with said actuating member thereby toinduce a second current in said coil independent of the rate of movementof said actuating member.

9. ina device for sensing a condition and operating an electricalcircuit in response thereto, a pair of iron cores each having a coilwound thereon at one end thereof and a permanent magnet between theopposite ends of said cores, an actuating member movable in response toa change in the condition being sensed, an armature opposed to the endsof said cores and movable into and out of engagement therewith, a motiontransmitting connection between said armature and said actuating memberso that said armature is movable with said actuating member toward saidcores until said armature is spaced a predetermined distance from saidcores whereupon the magnetic attraction causes said armature to snapinto engagement with said cores thereby to induce a current in saidcoils the vaiue of which is independent of the rate of movement of saidactuating member, and a spring connected between said actuating memberand said armature for urging said armature into engagement with saidactuating member but permitting movement of the latter away from saidcores while said armature remains in engagement therewith until theforce of said spring overcomes said magnetic attraction to pull saidarmature away from said cores thereby to again induce a current in saidcoils the value of which is independent of the rate of movement or saidactuating member.

l0. A device according to claim 9 including a spring urging saidactuating member away from said cores.

References @Cited in the tile of this patent UNITED STATES PATENTS3,035,520 Koeppen May 22, 1962

3. IN A TRANSDUCER FOR SENSING A CONDITION AND OPERATING AN ELECTRICALCIRCUIT IN RESPONSE THERETO INCLUDING A CORE HAVING A COIL WOUND THEREONAND A PERMANENT MAGNET ASSOCAITED THEREWITH, AN ARMATURE MOVABLE INTOAND OUT OF ENGAGEMENT WITH SAID CORE, AN ACTUATING MEMBER ADAPTED FORMOVEMENT IN RESPONSE TO CHANGE IN THE CONDITION BEING SENSED, A MOTIONTRANSMITTING CONNECTION BETWEEN SAID ARMATURE AND SAID ACTUATING MEMBRSO THAT SAID ARMATURE IS MOVABLE WITH SAID ACTUATING MEMBER TOWARD SAIDCORE UNTIL AND ARMATURE A SPACED A PREDETERMINED DISTANCE FROM SAID COREWHEREUPON THE MAGNETIC ATTRACTION CAUSES SAID ARMATURE TO SNAP INTOENGAGEMENT WITH SAID CORE THEREBY TO INDUCE A CURRENT IN SAID COILINDEPENDENT OF THE RATE OF MOVEMENT OF SAID ACTUATING MEMBER.